Would it be fucked up if message his ex?

I went through his phone and found a bunch of messages where he gives her mixed signals and tells her he loves her during the time we were togethor. I don't want to seem petty and bitter but lately I've been wanting to msg her to expose him. She doesn't know anything, she suspects it but he always had something to cover up.. He has been keeping me a secret for 2 years! She doesn't know anything about me because he fears she'll get mad at him and put him on child support.

-I kind of want to let her know he's brought her kids behind her back with me a couple of times. One time one of his daughters threw up and she went home wearing one my daughters spare outfits. When she asked him "oh your bitch has a baby too huh. Playing step daddy?!" He told her I was just a friend

-How he's been playing us both around the same time

- how I found out he brings the kids to his house full of weed edibles and cocaine

-he's taken the kids to the bar where he goes to drink

- and how he plans on taking her to court for the kids because he wants to have control over her.

- how he has so many free days and refuses to dedicate more time seeing his kids and being a father. He'd rather go be a drunk and spend time with his friends but she doesn't know that. He lies and makes excuses of why he can't see the kids. I've argued with him about this a couple of times to see his kids more. Told me to mind my business.

I know I sound bitter but he thought he was going to get away with hiding me and playing me for so long and never was going to get caught. He wants to have her thinking he's just working for the kids and just one day makeup and get back togethor if the chance ever arose. And I don't want to let that slide.

I lost my child (pregnancy). This guy physically threatened me to throw me down the stairs and harm my child.

I failed to realize what kind of man he was and finally opened my eyes. He showed me a different side this whole time and now everything is unbottling and I am noticing